Excerpts from the XBox site:
With HD DVD players already on the market and the HD DVD accessory set to ship
for Xbox 360™ this fall, it is more important than ever to understand how this hi-def thing works. How exactly do the movies you want to watch, the HD DVD player, and your HDTV all relate to each other? Many questions and much confusion surround which resolution and frame rate are best suited for viewing HD DVDs, but this basic primer should at least give you a proper understanding
of the situation as it relates to you, the viewer.
Read the whole article here.